Wind generation systems have received much interest as an alternative to fossil fuels plants. Wind generation systems have the disadvantage of providing fluctuating or intermittent power output due to the variability of wind speed. Additionally, there is a finite ramp up and ramp down (decay) function from individual wind turbines when wind speeds change. The decay function is generally of the order of several minutes. Models of short term fluctuations are well advanced, and variations can be predicted with high levels of confidence. Combining such models with physical turbine inertias, the power outputs from wind turbine farms is predictable and can be included in power system planning as a dispatchable resource.
There remains a limit to how much capacity credit can be given to a wind farm or individual wind turbine. This is particularly true where the wind regimen is not coincident with load demand. For example, in certain wind turbine farm locations, wind speeds are greatest when the system demand is lowest. Prices for wind energy and capacity will always, therefore, be discounted at a short run avoided cost rate unless there is very high confidence that load demand and wind turbine output overlap.
A solution to variable output from wind turbines is to provide storage for the excess energy. The energy may then be delivered to a grid when the wind turbine output drops off. From the supply side perspective, this is an availability enhancement tool to provide a spinning reserve and a firm source of supply. From the demand side perspective, the storage is a load shaping or leveling tool. New electrical storage technologies are able to provide fast response to load fluctuations and large scale shifting of energy from off-peak or low value time periods to peak periods.
Integrating an energy storage system and a wind based generator in either a single wind turbine form or in a group of turbines involves the selection of a capacity and storage duration which allows the output to be firmed up in an optimal fashion. If the cost of this energy storage system is such that the added benefits resulting from its installation including increased energy sales (less spillage), increased capacity payments, and ancillary service benefits amount to more than its operating and repayment costs, then the energy storage system becomes a viable option. In addition, the energy storage system improves the penetration levels of wind power generation and improves system parameters, such as power quality, voltage control, and overall load factor. By applying energy storage at distribution levels, localized benefits as well as summated transmission system benefits occur.
Thus, it would be an advancement in the art to provide a stable and constant power output from one or more wind turbine generators by employing the benefits of an energy storage system.